Multiple sequence alignment and three-dimensional structures of β-defensin peptides. Conserved cysteines are shown in bold in the sequence alignment. Accession numbers are as follows: P60022, O15263, P01475, P01476, P12028, P12029, P82172. A The NMR structure of human β-Defensin 1 (1KJ5). B The NMR structure of crotamine (1H50) showing the region of cationic residues (red) responsible for anti-microbial activity. Disulfide bridges are depicted in yellow